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From Wikipedia, the free encyclopedia

A countdown is a sequence of counting backward
to indicate the seconds, days, etc. remaining before an event
occurs or a deadline expires. Typical events for which a countdown
is used include the launch of a rocket or spacecraft, the explosion of a bomb, the start of a race, or the New Year. Countdown was first used by the 1929
German science fiction movie "Die Frau im Mond" by Fritz Lang to increase
the drama of the launch sequence of the story's lunar rocket.

The procedures for each launch are written carefully. For the
Space Shuttle, a five-volume set, Shuttle Countdown (KSC S0007),
often referred to as "S0007", is used. Rosie Carver, a technical
writer for United Launch Alliance, has
created at least 15,000 procedures for more than 300 missions since
the Solar Maximum Mission, which
launched Feb. 14, 1980. These documents are living documents, which
reflect new issues and solutions as they develop. Each mission
requires approximately 100 procedure books. [2]

Proceeding with the countdown depends on several factors, such
as the proper launch window, weather that permits a safe launch,
and the rocket and payload working properly.

The launch weather guidelines involving the Space Shuttle and
expendable rockets are similar in many areas, but a distinction is
made for the individual characteristics of each. The criteria are
broadly conservative and assure avoidance of possibly adverse
conditions. They are reviewed for each launch. For the Space
Shuttle, weather "outlooks" provided by the U. S. Air Force Range
Weather Operations Facility at Cape Canaveral begin at Launch minus
5 days in coordination with the NOAA National Weather Service
Spaceflight Meteorology Group at the Johnson Space Center in
Houston. These include weather trends and their possible effects on
launch day. A formal prelaunch weather briefing is held on Launch
minus 1 day, which is a specific weather briefing for all areas of
Space Shuttle launch operations. [3]

The launch window is a precise time during which aerospace
personnel launch a rocket so the payload can reach the proper
orbital destination.[4]

A hold is the suspension of the normal countdown process. This
can be done to investigate a technical process that has gone wrong,
or because of marginal weather at the launch pad.

Some holds are planned: they are done so the launch-support
computers can run automatic checks on the rocket.

Under some circumstances, a countdown may be recycled to an
earlier time. When that happens, launch personnel begin following
the countdown checklist from the earlier point. [5]

During communications for a countdown, the launch team uses
acronyms to keep channels open as much as possible. All Firing Room
console positions are assigned unique 'call signs' that are used by
the team for quick and positive identification of who is
talking.[6]. For
example, dialogue heard during the launch of a Delta II rocket carrying the Kepler Space Telescope on March 8, 2009,
included:

In the context of a rocket launch, the "T minus Time" is the
time before launch, e.g. "T minus 3 minutes and 40 seconds". The
last ten seconds are usually counted down aloud "10, 9, 8, 7, 6, 5,
4, 3, 2, 1, Lift off!" After a launch, most countdown clocks begin
to show Mission Elapsed Time, which is typically shown as "T plus."
The picture to the right shows "+ 00:00:00:07", approximately seven
seconds after liftoff.

The first known use of a countdown for a rocket launch occurred
in Fritz Lang's 1929
filmFrau im Mond.[8] In the
film, after each number the words "seconds to go" was repeated.

When counting down to the launch of an explosive, e.g. when
testing a new model of gun, it is customary to omit "5" from the
countdown sequence because "five" sounds too similar to
'Fire!'.

Film

At the start of films, a countdown sequence is printed on the head leader, to aid in
synchronizing the film. In film (but not television) the countdown
is in units of feet rather than time units.

The countdown ends just as "two" is displayed so that the
countdown isn't shown if the film is put on screen a little earlier
than intended. Although this sequence was usually not intended for
broadcast, being a cue device for a projectionist or TV producer,
it is sometimes used in modern-day spoofs to signify old film footage.

New Year's
Eve

In many New
Year's Eve celebrations, there is a countdown during the last
seconds of the old year until the beginning of the new year.
Additionally, countdowns are often used to count down the days
before special events, such as major holidays like Chinese New
Year and Christmas
and one's birthday.

Contents

Season 1

[1.1]

Richard Whiteley: As a
countdown to a brand new channel ends, a brand new Countdown
begins.

Episode of 7 January
1991

The word "wankers" was produced in the letters game.
Both contestants, Lawrence Pearce and Gino Corr, declared it. The
round was played again because of the offensive word, but the
out-take has featured on many clips shows. Gyles Brandreth was special guest at
the time.

Corr: We're a pair of wankers.Brandreth: They anticipated my next line: What is
Richard Whiteley doing asking for a definition of...?

Gotcha
episode

(omethings apears on the board)

Amanda: I've got 5.

Richard Whiteley: What?! 5? OK well how about
you?

Richard: No, 6. (Whitley puts his head in
his hands in disbelief)

Amanda: I've got diarrhoea! (refering to her
answer)

Richard Whiteley: Well, fantastic! What have
you got, Richard?

Richard: Yeah, I've got diarrhoea too!

Dictionary Corner:I have to say, we've got
diarrhoea as well! (to Whitley) Have you not got
diarrhoea?

Richard Whiteley: No, it's pathetic isn't
it?

Dictionary Corner: Well, it's a collection of
bowels incontinence!

Richard Whiteley: I think this show is a
wind-up for me!

[After pressing his buzzer and being told its not the
conundrum]

Richard: Well, I've got a limmerick:

There was an old man called Whiteley
Who's puns were always said frightfully
He took some viagra, and now like Niagra
He rushes and gushes twice nightly!

Jo:Anyway, my cat wasn't very well recently. I
think she got attacked by another cat and...it kind of got a...a
kind of a cut and it...it kind of got very sore and [the cat]
started weeping a bit. Anyway, the vet said it was PUSSIEROT.
(Laughter) Sorry. I'm trying my best. I'm sorry.

Jeff:Susie, anything to match PUSSIEROT?
(Laughter)

Susie Dent:I really hope not.

Episode of January 12
2009

Context:Jeff Stelling and Rachel Riley's first episode.

Jeff Stelling:It's cold and it's damp and it's
miserable and the electricity bill and the phone bill and the gas
bill have all arrived on the same day and it's still six months
until the Summer holidays. But are we downhearted?

Audience:NO!

Jeff:No, we are not because Countdown is back.
(Applause) And I know! I know what you're thinking. You're
thinking, "Who the heck am I?" Well, Stelling is the name. Six
consonants, two vowels and, in truth, the words I'm more used to
are "foul", "penalty", "referee", "blind as a bat"...

Umm, look, we're a couple of new faces and we've got a sparkling
new set as well here, but rest assured that this is the same
Countdown you've grown to love over the years.